Hindi
Study Question – Answers of Lesson-15 (3 and
4) written in notebook for a review on Tuesday, 8/3/16
Science
Read
the following content and answer the questions that follow in your science
note book and submit it on 8/3/16.
Mass
and weight are not the same.
Mass
is the amount of matter an object has. Mass is measured in Kilograms.
Weight
is a measure of how much gravity pulls on an object.
Unit
of force is Newton (N). Weight is a force so Weight is measured in Newton.
On
the Moon, gravity's pull isn't as strong as it is on Earth. The gravity on the
Moon is 1/6th that of Earth. So
a child who weighs about sixty Newton on Earth would only weigh about ten
Newton on the Moon, about the weight of a small dog.
Weight
changes with gravity, but mass always stays the same. The amount of matter in
an object doesn't change depending on where the object is in the universe. In
space, there is very little gravity. Astronauts in space are
practically
weightless and so they can float.
Gravitational And Frictional Force Magnetic Force
Gravity is a force that pulls things down to Earth. Earth’s gravity pulls
everything
downward. Without it, everything on our planet would float away.
Things with larger mass are not necessarily larger in physical
size. For example, a
balloon might be bigger than a baseball in diameter, but a
baseball has a greater mass. It will be explained that objects with greater
mass have a stronger force of gravity.
Earth's mass is much, much greater. When we throw a ball up into
the air, Earth's gravity pulls the ball down. Without gravity, the ball would
continue flying up and up.
Friction is the force resisting the relative motion of two surfaces in
contact.
Friction between solid objects is often referred to as dry
friction or sliding friction.
Fiction between a solid, a gas or liquid as fluid friction.
A common way to reduce friction is by using a lubricant, such as
oil, water, or grease, which is placed between the two surfaces.
Q1. Is mass and weight the same ?
Q2. Write two differences between mass and weight.
Q3. A child having a mass
35 kg is taken to the moon.
a. What is the child’s mass on
earth?
b. What is his/her mass on moon?
c. Will the child weigh the same on the moon as on earth?
